Radial menu user interfaces (UIs) (also referred to as circular or pie menu UIs) generally include a circular layout design in contrast to the more conventional linear menu UI paradigm. The layout and use differences of linear menu UIs and radial menu UIs are significant and both paradigms have advantages, disadvantages, and user appeal. Radial menus offer a distinct and wholly different visual and use experience as compared to linear menus. Linear menu UIs are typically located away from a user's current focus and are not always relevant contextually. However, acceptance of radial menu UIs continues to lag behind the more traditional linear menu paradigm.
Some radial menu UIs can be excessively cluttered, disorienting, and/or provide sub-optimal use experiences. For example, due in part to the more limited available display area for menu controls within a circular area, developers may attempt to put too many controls or options in each pie or wedge slice, resulting in smaller click targets which can lead to increased input errors and mistakes. Radial menu parameters such as item density, item spacing, item shapes, etc. have a direct influence on the usability and acceptance of a radial menu UI.